ADIS 16367

Hello

I am using IMU Adis 16367. I can read perfectly by spi any register individualy.

My problem is when  I am using burst read data collection. I send instruction 0x3E00 and CS reamaining in 0, i read the 22 bytes of datas bu I always get the same number, in all registers and it doesn't change in any time. Any ideas?  Do I need any control configuration?

Thank you very much.

Smainar

  • 0
    •  Analog Employees 
    on Mar 30, 2012 5:46 PM

    Hello Smainar,

    It sounds like you have a great start and a good position to work from.  When experiencing similiar issues, where you can read one register but cannot make the burst mode work, here are the two most common causes that I have observed:

    1. The SCLK maximum in Burst mode (1MHz) is lower than when you are reading a single register (2 MHz). See Table 2, page 5 of the ADIS16367 datasheet (Rev A) for this:
      http://www.analog.com/static/imported-files/data_sheets/ADIS16367.pdf#Page=05
    2. The Chip Select (~CS) line must be low for the entire sequence. You may need to put a scope probe on this line, to make sure that it is not rising in between each 16-bit sequeunce. See Figure 13, page 11 for the reference on chip select activity during the burst mode.
      http://www.analog.com/static/imported-files/data_sheets/ADIS16367.pdf#Page=11

    Also, this discussion provides a good overview of typical SPI issues that we have helped other cusotmers with in the past. It is based on another product, but the principles apply to the ADIS16367 as well.  http://ez.analog.com/message/44238#44238

    I hope that helps.  Please let us know what you find out and again, thank you for posting this question.

  • Hello NevadaMark and thank you for your post.

    Last week I was working in 500Khz clock and now, after your suggestion I fixed it to 125Khz (It is not needed, but...) . I haved checked and CS is remaining low in all 24 bytes of acquisition (2 bytes for comand in DIN and 22 for datas in DOUT).

    Individualy I can get gyro and acceleration in all axis, and datas are diferents and they change when I move IMU.

    If I work with burst read data, all values are equal in three axis, gyro and acc (3027 decimal) and it doesn't change when I move IMU: always fixed all to 3027. This could be understood if 0x3E00 wasn't a correct instruction for burst because: when I get one value, if I continue asking for values (until 12 to complete burst sequence) circular buffer inside of spi (i assume) would return again the same value asked whith 0x3E00 instruction. This could be the answer, I don't know. In datasheet you have suggested to me (adsi16407) burst sequence is 0x4200. (I have sent 0x4200 and answer from imu is always 12decimal in all registers, like with 0x3E00, all fixed but diferent answer from IMU).

    Could it be an error of manufacturing or datasheet? Otherwiese, any idea?

    Thank you again.

    Sergio Mainar

    PD:

    Individualy read in decimal:

    LOT_ID1: 10002

    LOT_ID2: 2322

    PROD_ID: 16367

    SERIAL_NUM: 95  (upper four bits mask-off done)

  • 0
    •  Analog Employees 
    on Apr 2, 2012 10:11 PM

    Hello Sergio. 0x4200 is the burst command for the ADIS16407, not the ADIS16367.  I offered that link to help understand the more basic opportunities we see in the SPI communication at a system level. Other customers have used this option in the ADIS16367, as well as the ADIS16360, ADIS16362, ADIS16364, ADIS16400 and ADIS16405, which all use the same start command.  An error in the datasheet is not likely, but I like to keep an open mind while we pursue the solution.  Could you share a scope plot of the SPI signals, that triggers off of the CS going low and shows the first two words of communication, with the vertical scale aligned well enough to see all 4 SPI signals? This has come up a few times, where single reads work fine and the burst mode does not.  The solution has typically been something subtle. Also, what the SUPPLY_OUT register reading, when you are reading just one register at a time?

  • Ok, next week I will have 2 scopes in my office, with two channels each one. So after Easter I will send to you.

    Thank you again.

  • 0
    •  Analog Employees 
    on Aug 2, 2018 4:33 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin